JPS603069A - Feature extracting device of read character - Google Patents

Abstract

PURPOSE:To extract the feature of a read character without any error and improve a character recognition rate by monitoring an increase or decrease in an integral output while avoiding a point where noise is easy to superpose. CONSTITUTION:The readout signal from a magnetic head 12 is amplified by an amplifier 13, and then integrated by an integrating circuit 18 and applied to an offset circuit 19 and a sample holding circuit 20. A monostable multivibrator 22 is triggered with the leading edge of the output pulse of a monostable multivibrator to output a pulse with constant time width. A monostable multivibrator 23 is triggered with the trailing edge of the output pulse of the monostable multivibrator 22 to generate a low-level output for a specific time. A monostable multivibrator 24 is triggered with the leading edge of the output of the monostable multivibrator 23 to output a pulse with the constant time width, and the monostable multivibrator 22 is triggered with the trailing edge of said pulse.

Description

[Detailed description of the invention] The present invention relates to an apparatus for extracting characteristics of read characters.

The character recognition device extracts and integrates the read waveform of the magnetic ink character on the card as a differential waveform, and then integrates the read waveform of the magnetic ink character on the card, and calculates the integral waveform at the midpoint of each position where the peak of the differential waveform selectively appears depending on the character. 1. Sampling with 1 non-pulse, 2 rotations, and comparing this sampling halt waveform and 2.2 integral waveforms by 2.2 sampling pulses. Japanese Patent Laid-Open Publication No. 103774/1983 discloses a device that extracts features and recognizes characters with a letter L.

However, in this character recognition device, the summation link and comparison are performed at the middle part of each position where the peak of the differential waveform selectively appears, but this middle part (d) is where the ink protrudes, dents, smudges, and noise is caused by snow. Because it hits a position where it is easy to ride, this noise will cause the integral waveform to fluctuate, making it difficult to accurately grasp its increase/decrease.However, it may not be possible to correctly extract the characteristics of the reading talent, making it impossible to recognize the bottled characters, and character recognition rate was low.

The object of the present invention is to provide a feature extraction device for read characters that avoids areas where noise is likely to occur and monitors increases and decreases in integral output in order to extract the features of nine characters without error. .

Please refer to the drawings below for misfired E! IIJ will be explained by giving examples.

Figure 51 shows an example of a character 111g recognition device to which the present invention is applied.

In this example, magnetic ink characters E13B recorded on a medium such as a cart such as a check are read and recognized. magnetic ink letters are magnetized. The magnetic head 12 detects the magnetization h on the card.
It reads the characters magnetically and outputs the differential waveform. As shown in Figure 2, the magnetic ink characters on the top of Horn 1 are divided into 7 equal flocks by dividing the character recording area 42 for one character (in this figure, the character 0 is recorded) with dividing lines ■ to ■. When divided into Peaks appear selectively at corresponding points according to the letters.
This is a timing chart when reading a magnetic letter "1", and the signal taken out from the magnetic head 12 has a lot of noise at YSII, which is between the points where the peak is selectively "1" and "1". After this bladder removal signal is amplified by an amplifier 1:3,
The signal is integrated by an integrating circuit 18 consisting of an operational amplifier] 4, a combiner J5, and resistors 16 and 17 to form a waveform as shown in FIG. A monostable multivibrator (hereinafter abbreviated as monomulti) 21 is triggered at the beginning of the read signal from the magnetic head 12 and has a time width t corresponding to the specified character width, as shown in FIG. 3 (c). ,
1: Produces a strong output pulse. Here, the magnetic ink characters all have their starting edges on the dividing line. Monomulti 22 is the origin of monomulti 21 (2 (7) standing" - 1 in 1).
Constantly 1? 7=] full width pulse is output, and the mono-multi 23 is triggered by the falling edge of the output pulse of the mono-multi 22, and when the output is constant it becomes ++jl (ffl level.The mono-multi 24 is triggered by the rising edge of the output pulse of the mono-multi 23. When triggered, it outputs a pulse with a certain time width, and the monomulti 22 is triggered at the falling edge of this pulse.+
The reading signal of the two pieces appears selectively depending on the dividing line (v ~ (peak) or the magnetic ink character at the point corresponding to the dot, but if the interval between these points is A, then the monomulti 22 .Therefore, the output of the monomulti 22 is as shown in Figure 3 (E).
The output of the monomulti 23 is as shown in Figure 3 (2), and the output of the mono multi 24 is as shown in Figure 3 (2).
The result will be as shown in (g). Zanopring pulse oscillator 25
At the rising edge of the output pulse of the monomulti 23, a lean blink pulse as shown in FIG. A comparison pulse as shown in Figure 3 (S) is generated. The sampling pulse and the comparison pulse are generated at points 7A apart before and after the point where the peak of the read signal from the magnetic field selectively appears. Sampling halt circuit 201-
1: From the switch 28 and the capacitor 29, the output signal of the integrating circuit 18 is sampled by the sampling pulse of the switch 28, and the output signal is sampled by the capacitor 29 (
tC, J:I) Bold. The offset circuit 19 is an integrator circuit 11 when the potential change in the output signal of the integration circuit 8 is small.
It is provided to prevent the signal from being determined as a potential change, and is composed of resistors 31, 32, diodes 33, 34, and variable resistors 35, 36, and is configured to raise and lower the output signal of the integrating circuit 18 by a predetermined level. Modify the blade. The comparator 37 compares the correction output of the circuit 19 with the output of the Zumblingpoort circuit 20, and when the former is larger than the latter, the output becomes 1, and when the former is smaller than the latter, the output becomes 0. Become. Compare Lake 38
is the ratio of the downward correction output of the offset circuit 19 and the output of the sampling hold circuit 2o, and when the former is smaller than the latter, the 111 force becomes //1", and the former is larger than the latter, which is output to Hl, 14. becomes “o”. The D flip-flops 39 and 40 latch the outputs of the comparison pulse comparators 37 and 38, and therefore, the output of the summing hold circuit 2o is compared with the output of the offset circuit J9 at the generation timing of the comparison pulses. It is done virtually. For this reason, as shown in FIG. 3(d), there are points around the point where the peak of the read signal (differential waveform) from the magnetic head 12 selectively appears, and there are points separated by -A before and after the point where the peak of the read signal (differential waveform) from the magnetic head 12 appears. However, by performing the above sampling S and the above comparison C and detecting the increase/decrease relationship in the output signal of the integrating circuit 18, the features of the nine read characters can be correctly extracted as a take as shown in FIG. Ru. The identification circuit 41U reads the output take of the D flip-flop 39.40 by the pulse from the comparison pulse generator 26 into the ++4i in which the output signal of the monomulti 21 is manually inputted, and divides each bit into the internally stored unique classification pattern. The read character is recognized by determining whether it is valid or invalid and comparing it with each character pattern in internal memory.

If the above sampling and comparison are performed at both points before and after the point where the peak of the differential waveform from y l' 12 selectively appears in the magnetic field, increases and decreases in the integral output can be detected accurately while avoiding points where noise is likely to occur. can do. However, due to the relationship with noise and accuracy problems due to the interval between sampling and comparison, upstream summing and comparison are performed at 7A before and after the point where the peak of the differential waveform from the magnetic head selectively appears. It is best to do so.

As described above, according to the present invention, since the increase or decrease in the integral output is checked while avoiding points where noise is likely to occur, the characteristics of the read character can be
It is possible to extract the characters without J, and as a result, the character recognition rate is improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an application example of the present invention;
+J, diagram showing the formation of the first block of magnetic ink characters;
FIG. 3 shows the timing at the time of one reading recognition in the above application example. 22-24 - Mo, No. 1, 254 No. 1/Flink pulse oscillator, 26. Ratio 1 medical pulse oscillator. 6 Heli O on ρ − hehe,

Claims (1)

[Claims] By extracting the character reading signal as a differential waveform and integrating it, and by comparing this integral waveform with its sampling hold waveform, the integral is calculated before and after the point where the peak of the differential waveform selectively appears. In a read character feature extraction device that extracts the features of read characters by looking at the increase/decrease relationship in the waveform, a timing signal is generated at a point within half the interval between adjacent peak points, centering on the peak point in the differential waveform. provide a means to generate
The above sampling and comparison are performed according to the above timing signal, so that the read character'? ,! ? Feature extraction device.